Παραπομπή APA

Gupta,P.K, & Hira,D.S. (1991). Problems in Operations Research: Principles and solutions. S.Chand & company Ltd.

Παραπομπή Chicago Style

Gupta,P.K, και Hira,D.S. Problems in Operations Research: Principles and Solutions. New Delhi: S.Chand & company Ltd, 1991.

Παραπομπή MLA

Gupta,P.K, και Hira,D.S. Problems in Operations Research: Principles and Solutions. S.Chand & company Ltd, 1991.